[Bug-gsl] error in multifit/multiwlinear.c in gsl-2.3 and gsl-2.4

[Vlad Koli]

Hi,

There is an error in file multifit/multiwlinear.c. It is present at least  
in sources for gsl-2.3, gsl-2.4. 

  Line 69 should be replaced (I think) from:

 else if (X->size1 != work->n || X->size2 != work->p)

   to

 else if (X->size1 != work->nmax || X->size2 != work->pmax)  // vk:

Values of "work->n", "work->p" for this file, for example, are nulls.

After this replacement, re-compilation, and re-installation the tests 
began to work correctly.


Check, for example the test file "linfit-pseudoinv.c" quoted below.  

** compilation:

 cc -o a -lm -lgsl -lgslcblas linfit-pseudoinv.c 

**  execution: 

 ./a

** result:

> gsl: multiwlinear.c:73: ERROR: size of workspace does not match size of 
> observation matrix
> Default GSL error handler invoked.
> Aborted


Regards,
Vladimir Koliadin


----- begin file: linfit-pseudoinv.c:---------
// compile:
//     cc -o a -lm -lgsl -lgslcblas linfit-pseudoinv.c 
#include <stdio.h>
#include <gsl/gsl_multifit.h>


double tol = 1.e-08; // tolerance

main()
{
     
    int n = 3; // observations
    int m = 2; // parameters 

    size_t rank;   // rank
    double chisq;  // sum of squares of residuals

    // allocate:
    gsl_vector *x = gsl_vector_alloc(m); // solution 
    gsl_vector *y = gsl_vector_alloc(n); // data 
    gsl_vector *w = gsl_vector_alloc(n); // weights

    gsl_matrix *A = gsl_matrix_alloc(n, m);
    gsl_matrix *cov = gsl_matrix_alloc(m, m); // covariances

    gsl_multifit_linear_workspace* wsp = gsl_multifit_linear_alloc (n, m);


    // set matrix
    gsl_matrix_set(A, 0,0, 1.);
    gsl_matrix_set(A, 0,1, 1.);
    gsl_matrix_set(A, 1,0, 2.);
    gsl_matrix_set(A, 1,1, 2.);
    gsl_matrix_set(A, 2,0, 3.);
    gsl_matrix_set(A, 2,1, 3.);

    // set data 
    gsl_vector_set(y, 0, 1.);
    gsl_vector_set(y, 1, 2.);
    gsl_vector_set(y, 2, 3.1);

    // set weights
    gsl_vector_set_all(w,1.);
    gsl_vector_set(w, 0, 0.);
    gsl_vector_set(w, 2, 100.);


    gsl_multifit_wlinear_svd (A, w, y,  tol, &rank, x, cov, &chisq, wsp);
 

    printf("solution: x=%.4f  y=%.4f   (rank=%d, chi2=%.3f)\n", 
            gsl_vector_get(x,0), gsl_vector_get(x,1), rank, chisq);


}
----- end file: linfit-pseudoinv.c:---------